1. Field of the Invention
This invention relates to covers used to prevent loss of heat during cold weather and loss of cool air during hot weather that is caused by a ceiling trap door and/or pull down attic ladder or stairs in a building.
2. Description of the Prior Art
For all homes with an attic trap door and/or pull down attic ladder, there is typically only a thin plywood closure used to provide insulation for the area of the trap door or pull down ladder (opening). This opening creates a gap in the insulation of the building. The plywood door typically has an insulating R-Factor of 0.5 or less, while the rest of the attic has insulation of R-19 or greater. There have been a number of inventions to date that have addressed this problem with two main approaches.
There are a number of one-piece covers. U.S. Pat. No. 4,299,059 discloses a ceiling door that is insulated and to which an attic ladder is attached. U.S. Pat. No. 4,151,894 discloses a one-piece cover for an attic opening that fits over the attic door. It is double walled and able to contain a layer of insulation. U.S. Pat. No. 4,281,743 similarly provides a one-piece cover for an attic opening that fits over the attic door. This cover, however, is a shell, comprised of multiple pieces that need to be assembled in a tongue and groove design into which insulating panels are inserted. U.S. Pat. No. 5,475,955 discloses a two-piece shell that is able to contain insulation. U.S. Pat. No. 4,832,153 is also a one-piece cover for an attic opening. This cover consists of detachable components that can be stored or attached with assembly components to serve as an insulating cover. U.S. Pat. No. 4,928,441 discloses an inverted tub shaped cover that is hinged to an attic floor. U.S. Pat. No. 5,271,198 discloses a compartmentalized plastic or fiberboard shell with a moisture barrier insert that can accommodate insulation. U.S. Pat. No. 5,628,151 discloses a one-piece shell with multiple pockets that can hold insulation.
There have also been other two-piece covers. U.S. Pat. No. 4,344,505 discloses a stationary frame with a hinged door that opens to an upright position. The door and frame are made of insulated material and covered with wood furring for securing the hinges to the door and frame. The door merely rests on the frame. U.S. Pat. No. 4,591,022 discloses a frame and door, but the door is in three pieces. In order to open the door, it collapses in an accordion manner to gain access to the attic. The frame consists of components that are attached and secured to the attic floor with hinges.
U.S. Pat. No. 4,312,423 discloses an all in one approach for a ladder, insulating cap and packaging container.
With each patent, there are some consistent elements. Each patent referenced above is not in itself an insulating solution. Rather, it is a shell made of various materials into which one can insert insulation. Thereafter, each solution has distinguishing ways to affix the cover to the attic and open the cover to access the attic. The shells require some assembly.